The invention concerns a valve train of an internal combustion engine, said valve train comprising a cam follower acting on at least one gas exchange valve, said cam follower being loaded by a cam from whose base circle an optionally actuable additional cam piece for generating an additional lift of the gas exchange valve projects.
DE 30 03 566 A1 discloses a valve train whose camshaft comprises a control shaft that is axially displaceable in the camshaft. An additional cam projects out of the base circle of a cam of the camshaft illustrated in FIG. 1. This additional cam is received in a pocket of the cam for a radially outward movement out of the pocket. For obtaining an additional lift on the outlet valve, the control shaft can be displaced in axial direction such that a radial collar of the control shaft causes an outward movement of the additional cam.
A drawback of the aforesaid device is the immense structural complexity that leads to high costs. The camshaft must have a hollow configuration and comprise the additional control shaft. A complex and expensive operating device becomes necessary. In addition, it must be assured that the additional cam is not lost during phases of high rotational speed of the camshaft.